/*
package itHsuSE.demo2;


public class Work5 {
}

class Circle{
    public double r;
    public Circle(double r){
        this.r=r;
    }
    public double zhouchang(){
        return 2*Math.PI*r;
    }
    public double mianji(){
        return Math.PI*r*r;
    }
}*/
